酸性和中性水田土壤施用硅肥的效应研究 Ⅰ.对土壤pH、Eh及硅动态的影响

Effect of Silicon Fertilizer in Acid and Neutral Paddy Field Soils Ⅰ.Effect on Dynamic Changes of pH,Eh and Si in Soil Solution

分别选取酸性和中性水田土壤进行盆栽试验,研究施用硅肥对水稻各生育期土壤溶液pH、Eh及硅浓度的影响。结果表明,淹水种稻后酸性土壤pH迅速升高,而中性土壤pH降低,然后均趋于中性;Eh的变化基本均呈近似＂W＂形;土壤溶液硅浓度则经历了一个先升高后下降并趋于稳定的变化过程。与对照相比,单施高炉渣或高炉渣与葡萄糖配施处理在提高土壤溶液pH和Eh、增加硅浓度方面的效果较为明显,尤其在酸性水田土壤上表现得更为突出;偏硅酸钠的施用效果只是在水稻生长的某一时期在中性水田土壤上表现得相对明显;单施葡萄糖会降低土壤Eh,提高生育前期土壤溶液中的硅浓度。在水稻全生育期内,高炉渣与葡萄糖配施处理的土壤溶液中硅浓度升高的幅度最大,在酸性水田土壤和中性水田土壤上分别是对照处理的1.40（最小倍数）~4.93（最大倍数）倍和1.19（最小倍数）~2.72倍（最大倍数）,说明施用高炉渣硅肥,可明显提高土壤硅素供应水平,对促进水稻生长、提高水稻产量有重要意义。

Pot experiments were conducted to study the effects of silicon fertilizer on the dynamic changes of pH, Eh, silicon concentrations in soil solutions of acid and neutral paddy field soils in northern China during the growth stages of rice. The mechanisms of different types of sili- con fertilizer on improving soil silicon supplying ability were investigated. The results showed that pH value increased in acid soil, however it decreased in neutral soil, and finally both approached to neutral pH. The pH value of soil solutions in the treatments with blast furnace slag or mixture of blast furnace slag and glucose increased obviously in acid paddy field soil, while the increase of pH was more pronounced in the treatment with sodium metasilicate in neutral paddy field soil. The Eh of all treatments in the two types of soil decreased sharply firstly, and gradually reached the bottom, then increased rapidly to a peak after the water was drained away; when soil was drowned again, the Eh de- creased to another bottom, and then increased slightly. The Eh varied greatly between acid and neutral soil. In acid paddy field soil, Eh in- creased in the treatments with blast furnace slag or sodium metsilicate, whereas it decreased in the treatment with glucose. The silicon con- centration in soil solutions of all treatments increased to a peak, then decreased gradually, and stabilized at a constant value. The silicon con- centration in soil solutions increased in the early growth stage of rice because of application of silicon fertilizer, and the increase was most ob- vious in the treatment with glucose or mixture of blast furnace slag with glucose. The silicon concentration in the treatment with sodium metasilicate was higher than that in the treatment with blast furnace slag in neural paddy field soil at early growth stage of rice; in the late growth stage of rice, the silicon concentration in the treatment with silicon fertilizer was higher than that in the treatment with glucose. In acid paddy field soil, the effects of blast furnace slag or mixture of blast furnace slag with glucose on silicon concentration was greater than that in the treatment with sodium metasilicate. In the whole growth stage of rice, mixed application with furnace slag and glucose increased the sili- con concentration in the soil with the maximum increase rate. The silicon concentrations were 1.40 （the smallest muhiple）~4.93（the largest multiple） time and 1.19 （the smallest multiple）~2.72 （the largest multiple） time higher in acid and neutral paddy soils respectively, com- pared to the untreated soil. Our study has shown that silicon fertilizers from blast furnace slag can improve the silicon-supplying capacity in the soil and increase the growth and yield of rice.